基于阻抗模型的不确定环境下微纳操作力跟踪控制策略研究

Research on control strategy of micro and nano operating force tracking in uncertain environment based on impedance mode

微机电系统在生物医学领域具有巨大的应用潜力,以压电陶瓷为基础设计的压电驱动系统在微纳操作高精度控制领域发挥着重要作用。在各领域的实际应用中,微操系统与环境的交互一直是研究的热门方向。由于微尺度下跟踪力误差相比宏观尺度下更不可忽略,因此微操作臂与环境接触力的精准控制是提高微操作准确度的关键。为此本文提出一种力跟踪阻抗控制策略,能够在操作过程中实现对接触力的精确跟踪。考虑到阻抗模型对环境参数要求较高,本文提出了扩展卡尔曼滤波器对外部环境参数进行在线估计的方法。实验结果表明,所提控制方法能够成功实现微操作臂-环境交互模型的力跟踪控制并且有良好的跟踪精度,力跟踪平均绝对误差为7.82 mN,均方根误差为10.16 mN,因此该方法对不确定性环境下接触力的精确跟踪具有可行性。

Micro-electro-mechanical system(MEMS)has great potential application in biomedical field.The piezoelectric drive system based on piezoelectric ceramics plays an important role in the field of high-precision control of micro-nano operation.In the practical application of various fields,the interaction between micro system and environment is always a hot research direction.Since the tracking force error at the micro scale is more non-negligible than that at the macro scale,the precise control of the contact force between the micromanipulator and the environment is the key to improve the accuracy of the micro operation.Therefore,a force tracking impedance control strategy is proposed in this article,which can accurately track the contact force during operation.Because the impedance model requires high environmental parameters,an extended Kalman filter is proposed to estimate the external environmental parameters online.Experimental results show that the proposed control method can successfully realize the force tracking control of the micro-manipulator environment interaction model and has good tracking accuracy.The average absolute error of force tracking is 7.82 mN,and the root mean square error is 10.16 mN.Therefore,the method is feasible to accurately track the contact force in uncertain environment.